Lasers
Lasers
Other books in The Lucent Library of Science and Technology include: Black Holes Comets and Asteroids Genetics Global Warming
THE LUCENT LIBRARY OF SCIENCE AND TECHNOLOGY Lasers by Don Nardo San Diego Detroit New York San Francisco Cleveland New Haven, Conn. Waterville, Maine London Munich
On cover: A scientist focuses intently as he engages in laser research. 2003 by Lucent Books. Lucent Books is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Lucent Books and Thomson Learning are trademarks used herein under license. For more information, contact Lucent Books 27500 Drake Rd. Farmington Hills, MI 48331-3535 Or you can visit our Internet site at http://www.gale.com ALL RIGHTS RESERVED. No part of this work covered by the copyright hereon may be reproduced or used in any form or by any means graphic, electronic, or mechanical, including photocopying, recording, taping, Web distribution or information storage retrieval systems without the written permission of the publisher. LIBRARY OF CONGRESS CATALOGING-IN-PUBLICATION DATA Nardo, Don, 1947 Lasers / by Don Nardo. p. cm. (The Lucent library of science and technology) Summary: Discusses the scientific discovery and development of the use of high-intensity light, called laser, and its use in our daily lives. Includes bibliographical references and index. ISBN 1-59018-104-2 1. Lasers Juvenile literature. [1. Lasers.] I. Title. II. Series. TA1682.N36 2003 621.36'6 dc21 2001008206 Printed in the United States of America
Table of Contents Foreword 8 Introduction 11 Going Where No One Has Gone Before Chapter 1 14 The Development of Lasers Chapter 2 28 Lasers in Science and Industry Chapter 3 40 Lasers in Communication and Marketing Chapter 4 52 Military Applications of Lasers Chapter 5 63 Medical Uses of Lasers Chapter 6 74 Lasers in Entertainment Chapter 7 86 The Future of the Laser Notes 97 For Further Reading 99 Works Consulted 101 Index 105 Picture Credits 111 About the Author 112
Foreword The world has changed far more in the past 100 years than in any other century in history. The reason is not political or economic, but technological technologies that flowed directly from advances in basic science. Stephen Hawking, A Brief History of Relativity, Time, 2000 The twentieth-century scientific and technological revolution that British physicist Stephen Hawking describes in the above quote has transformed virtually every aspect of human life at an unprecedented pace. Inventions unimaginable a century ago have not only become commonplace but are now considered necessities of daily life. As science historian James Burke writes, We live surrounded by objects and systems that we take for granted, but which profoundly affect the way we behave, think, work, play, and in general conduct our lives. For example, in just one hundred years, transportation systems have dramatically changed. In 1900 the first gasoline-powered motorcar had just been introduced, and only 144 miles of U.S. roads were hardsurfaced. Horse-drawn trolleys still filled the streets of American cities. The airplane had yet to be invented. Today 217 million vehicles speed along 4 million miles of U.S. roads. Humans have flown to the moon and commercial aircraft are capable of transporting passengers across the Atlantic Ocean in less than three hours. The transformation of communications has been just as dramatic. In 1900 most Americans lived and worked on farms without electricity or mail delivery. Few people had ever heard a radio or spoken on a telephone. A hundred years later, 98 percent of American 8
Foreword 9 homes have telephones and televisions and more than 50 percent have personal computers. Some families even have more than one television and computer, and cell phones are now commonplace, even among the young. Data beamed from communication satellites routinely predict global weather conditions and fiber-optic cable, e-mail, and the Internet have made worldwide telecommunication instantaneous. Perhaps the most striking measure of scientific and technological change can be seen in medicine and public health. At the beginning of the twentieth century, the average American life span was forty-seven years. By the end of the century the average life span was approaching eighty years, thanks to advances in medicine including the development of vaccines and antibiotics, the discovery of powerful diagnostic tools such as X rays, the life-saving technology of cardiac and neonatal care, and improvements in nutrition and the control of infectious disease. Rapid change is likely to continue throughout the twenty-first century as science reveals more about physical and biological processes such as global warming, viral replication, and electrical conductivity, and as people apply that new knowledge to personal decisions and government policy. Already, for example, an international treaty calls for immediate reductions in industrial and automobile emissions in response to studies that show a potentially dangerous rise in global temperatures is caused by human activity. Taking an active role in determining the direction of future changes depends on education; people must understand the possible uses of scientific research and the effects of the technology that surrounds them. The Lucent Books Library of Science and Technology profiles key innovations and discoveries that have transformed the modern world. Each title strives to make a complex scientific discovery, technology, or phenomenon understandable and relevant to the reader. Because scientific discovery is rarely straightforward, each title
10 Lasers explains the dead ends, fortunate accidents, and basic scientific methods by which the research into the subject proceeded. And every book examines the practical applications of an invention, branch of science, or scientific principle in industry, public health, and personal life, as well as potential future uses and effects based on ongoing research. Fully documented quotations, annotated bibliographies that include both print and electronic sources, glossaries, indexes, and technical illustrations are among the supplemental features designed to point researchers to further exploration of the subject.
Introduction Going Where No One Has Gone Before O ne day in 1960 something happened that seemed almost magical to many people. Dr. Theodore Maiman put into operation a device that gave off a thin, bright red beam of light. This remarkable device was the world s first laser. It was called a ruby laser because Maiman passed ordinary light through a ruby to produce the laser light. Since that day hundreds of different kinds of lasers have been made, and thousands of practical uses have been found for these modern supertools. Until the invention of the laser, using powerful beams of light was an idea that appeared mainly in science fiction. The first important example was in H.G. Wells s classic The War of the Worlds (published in 1898). In the novel sinister Martians use a terrifying heat ray to attack the earth. Later, in the early comic strips, space heroes like Flash Gordon and Buck Rogers used deadly ray guns to fight their archenemies. Certainly, most people today are familiar with the exploits of Captains Kirk, Picard, Janeway, and Archer of the Starships Enterprise and Voyager. Fans of the Star Trek TV shows and movies know all about phasers and photon torpedoes, those fabulous, futuristic weapons 11
12 Lasers of light. Equally famous are the light swords wielded by Luke Skywalker, Darth Vader, and other characters in the popular Star Wars films. Of course all the devices mentioned above are destructive. This can be misleading, for science fiction is filled with examples of light being used for constructive purposes as well. For instance Star Trek s characters use a small light source to perform operations, and they use beams of light to take apart thick metal walls, to repair broken circuits, and to generate holograms to create realistic virtual environments on the holodeck. Such advanced technology does not utilize normal everyday light, of course. It requires laser light, which is very different from ordinary natural light. The laser Dr. Theodore Maiman, creator of the first successful laser, examines an early version of the device. The cube inside is the ruby crystal that emitted the laser beam.
Going Where No One Has Gone Before 13 produces light that has been amplified, that is, made considerably brighter and more powerful. It took human beings, in their never ending search for new knowledge, to go beyond mere light, to invent the laser, and to take advantage of its marvelous properties. Just as Captains Kirk and Janeway go where no one has gone before, scientists saw a light no one had seen before and put it to use for the good of all people. Indeed, on that day in 1960 when the ruby laser began to glow, a new era began for humanity. The light no one had ever seen suddenly began to change science fiction into science fact. As lasers continue to advance rapidly and do more tasks in a wide range of scientific, medical, industrial, and commercial areas, it seems more and more likely that the society depicted in the world of Star Trek may be much closer than most people imagine.